Super Soaker Central

CPSC-97

CPSC-97

Posted: Fri Jul 16, 2010 2:42 am

by chaosfox97

Hello, I just recently joined the forum but I have been looking at this website for a while. After looking at several plans I decided to make a CPS gun with a cylindrical pressure chamber. But instead of having a pressure chamber had an opening on only one end, I decided to design it with both ends, but I am also going to design one with a single end on the pressure chamber, and see which is best, according to you, the members of Super Soaker Central. I'm going to call it the CPSC-97; which stands for Constant Pressure System: Custom. I made these with PVC Design, a program someone made and posted a download link on this forum.

This is the Mark I version (with double ended chamber):

This is the Mark II version (with single end chamber):

And this is the backpack tank that can be attach to the right part of the tee connected to the reservoir:

Vote with the poll on a new thread, titled "CPSC-97 Voting" for which is your favorite or which you think is the best. This poll will be active for 28 days, beginning on 7/ /2010

Re: CPSC-97

Posted: Fri Jul 16, 2010 3:59 am

by zeda.beta

The pump seems a bit unusual, and it makes sure that you have no chance of pumping and firing at the same time. Also, is it supposed to take the gun nozzle backwards when pumping too? Because right now it looks like you intend to have the entire front of the gun move when you pump. That just wastes energy.

Plus, the PC might work, but it leaves the question of how much, (or how little) of a stream is going to be created when you open the ball valve.

Re: CPSC-97

Posted: Fri Jul 16, 2010 6:32 am

by chaosfox97

The large tee on the barrel that is connected to the pump isn't connected to the barrel, it is larger so it simply slides over it, it also gives support and three different ways of holding it, by the bottom like a shotgun, in the middle like a vertical grip, or at the top with the little corner thing, though I don't know why I would use it. About firing it, most homemades that I've seen don't let you fire and pump at the same time, but the cover provides a handle and I plan on add a torque bar to act some what of a trigger. If all else fails I can remove the handle and just hold on to the gun on the pump and the valve. What I'm asking though is if the design is good enough so I can move out of the brainstorming/developing/blueprints stage and actually make it.

Re: CPSC-97

Posted: Fri Jul 16, 2010 12:23 pm

by cantab

1) A big gap between the firing valve and the nozzle is bad, since water will get left there and then drip out of the nozzle.

2) More seriously, by fixing both ends of the pressure chamber, you prevent the LRT from expanding lengthways. Normal cylindrical pressure chambers expand in width AND length.

Re: CPSC-97

Posted: Fri Jul 16, 2010 6:15 pm

by chaosfox97

Okay, I'll move the valve closer to the nozzle, but is it really necessary to use only one end of the LRT, or can I leave it as is, because that's what makes my design different. Other than that do you think I'm ready to start building?

Re: CPSC-97

Posted: Fri Jul 16, 2010 6:46 pm

by cantab

Well pinning both ends means the LRT can only expand in width. I think that is liable to hinder performance. But I don't know.

Re: CPSC-97

Posted: Fri Jul 16, 2010 8:46 pm

by zeda.beta

The lrt can expand 50% widthwise, and around 100-150% lengthwise, so pinning both sides would remove a lot of the power from your gun.

Re: CPSC-97

Posted: Fri Jul 16, 2010 9:40 pm

by C-A_99

It would also increase the chances of bladder rupture due to added stress.

Re: CPSC-97

Posted: Sat Jul 17, 2010 3:21 pm

by Silence

People have suggested something that slides along the length of the barrel. Hard to do though.

McMaster-Carr's numbers say that LRT will expand to 8x its rest width and 3x its rest length.

Anyway, there are other things you could try if you're looking to do something unique. Making a spherical bladder (using balloons) hasn't been documented very well. Or maybe an air chamber with a piston inside (basically a mini-Supercannon II), so you can reduce dropoff to CPS-type levels? A unique shape, better ergonomics, etc? A well-balanced onboard reservoir? There are lots of options that might be more viable than a double-ended bladder, although I agree that the latter would be interesting and unique.

Re: CPSC-97

Posted: Sat Jul 17, 2010 8:16 pm

by chaosfox97

Okay, thanks guys, I'll revise my plans and post them later. BTW, I already made a spherical bladder using three air balloons, so its partly done. Perhaps I can use the same general skeleton, but make three models, one with a spherical single end, one with a cylindrical single end, and one with a cylindrical double sided end, test them, and compare the results. Yeah... But what size should I make the barrel and most of the gun, 3/4 or 1/2?

Re: CPSC-97

Posted: Sat Jul 17, 2010 8:44 pm

by Fredcompany

three air balloons?
That'll be nowhere near powerful enough.
You need at least 25.

Re: CPSC-97

Posted: Sat Jul 17, 2010 10:25 pm

by chaosfox97

Okay then, but they're pretty thick...

Re: CPSC-97

Posted: Sat Jul 17, 2010 11:48 pm

by cantab

I've looked at your design again, and I've noticed something - the bladder can expand lengthways after all! The back is fixed to the bulk of the gun, but the front isn't rigidly, since the barrel can slide through the tee on the pump handle. So it might perform alright after all.

On pipe dimensions - the run from the pressure chamber outlet to the nozzle needs to be wide for best performance, so if you want a big blast. The diameter of the pump shaft affects the behaviour of the pump - larger diameter means more water pumped per stroke but more force needed to do so. The rest of the gun really doesn't matter, so narrow diameter is probably best for compactness and light weight.

One other point - why not swap around the position of the check valve and the elbow by the reservoir. Check valve is horizontal and you can bring the reservoir right up against the pump cylinder, making the gun more compact and with some zip ties you can easily reinforce the gun.

Re: CPSC-97

Posted: Sun Jul 18, 2010 12:40 am

by chaosfox97

Holy crap, I designed this and I didn't even know that, thanks cantab! For the main body I think I'm going to go with 3/4 because I have a few nozzles that size.

Okay so adjustments to be made: Make main body 3/4", switch elbow and check valve by reservoir, move ball valve in front of tee so it's directly behind the nozzle, make the nozzle a female non-threaded to male threaded adapter for multiple nozzles, make elbow by reservoir a tee so I can add a backpack, make the ends of the tee for the back pack threaded so I can screw on a cap when not in use.

I'll post two models, one with a dual end chamber, and one with a single end chamber, and I'll start a new vote.

Re: CPSC-97

Posted: Sun Jul 18, 2010 1:19 am

by chaosfox97

Already finished:

This is the Mark I version (with double ended chamber):

This is the Mark II version (with single end chamber):

And this is the backpack tank that can be attach to the right part of the tee connected to the reservoir:

Vote with the poll on a new thread, titled "CPSC-97 Voting" for which is your favorite or which you think is the best. This poll will be active for 28 days, beginning on 7/17/2010